tools: docstring for nested submodules

[aspeddro]

The output doesn't print docstrings for nested submodules in interface files.

Example: API Docs for Core.Math.Constants

• Core__Math.resi

Now

dune exec -- rescript-tools doc ~/Desktop/projects/rescript-core/src/Core__Math.res | head

{
  "name": "Core__Math",
  "docstrings": ["Functions for interacting with JavaScript Math.\nSee: [`Math`](https://developer.mozil
la.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math)."],
  "items": [
  {
    "id": "Core__Math.Constants",
    "name": "Constants",
    "kind": "module",
    "docstrings": ["Mathematical Constants"],

Other Change

• Print deprecated field for module

[zth]

Great!